ASoC: msm8952: add support for dynamic wsa881x detection on 3.18

Add support in machine driver to be able to parse device tree
for all possible wsa881x that are supported in the target,
find out from ALSA core about how many wsa881x out of the list
of devices passed from device tree are present in the target and
already registered with ALSA as codec, and eventually register
those wsa881x devices (which are present) as AUX codec to be used
with the sound card.

Change-Id: I69a5cf7d542178aca97eb0dd91e5b35e23467c93
Signed-off-by: Simmi Pateriya <simmip@codeaurora.org>